TOTAL SYNTHESIS OF (+)-4-DEOXYGIGANTECIN

A total synthesis of a non-adjacent bis-tetrahydrofuranyl annonaceous acetogenin, (+)-4-deoxygigantecin (1) is described. Mono-tetrahydrofur an building block (10), of which the synthesis from (-)-muricatacin (8 ) had been described in an earlier report, was converted to bis-MOM et her (9) through two-step reactions. Transformation of this compound in to non-adjacent bis-tetrahydrofuran unit (5) was carried out by a twel ve-step sequence of reactions. Pd(0)-catalyzed cross coupling reaction between 5 and iodinated butenolide (7), which had been prepared from( S)-(-)-ethyl lactate, led to enyne (4). Finally, this compound was con verted to (+) -4-deoxygigantecin (1) by two steps. (C) 1998 Elsevier S cience Ltd. All rights reserved.